1. Field of the Invention
The present invention relates to removing offensive odors from cork. Specifically, the present invention relates to removing 2,4,6-trichloroanisole (TCA) which has a characteristic odor.
2. Description of the Background Art
Cork has unique characteristics. It is lightweight and has a high degree of resilience. Additionally, it has excellent gas and liquid sealing properties, and has stability against solvents such as alcohol. Furthermore, it is a hygienic material which is food-safe and not harmful to human beings, and has no intrinsic odor.
Because of the above mentioned characteristics, cork has been widely utilized as stoppers for casings such as bottles filled with liquor such as wine, brandy or whiskey, or casings packed with various kinds of foods.
However, in spite of having no intrinsic odor, offensive odor is encountered on cork stoppers on rare occasions. This odor, when present, deteriorates the quality of the contents of the bottles or casings sealed by the cork. Recently, by various studies, 2,4,6-trichloroanisol (TCA) has been identified as the substance which originates the offensive odor. TCA is considered as the substance produced by moulds from 2,4,6-trichlorophenol (TCP) which is utilized in agents conventionally used to spray to cork oak. Also, in "Journal of Agricultural and Food Chemistry", (1982) pages 359 to 362, presumption is given that 2,4,6-trichlorophenol and other related chlorinated compounds originate from chlorination of a liquid-related substance during the chlorinate bleaching used in the processing of the cork and that these compounds are later extracted into the liquor, such as wine. Similar consideration that a clorinate agent is the source of the odor substance has been given in "Science des Aliments" (1984), pages 81 to 93. In the discussion, it has been pointed out that the 2,4,6-trichloroanisol is derived from pentachlorophenol or other chlorinated pesticides applied to the tree. Further consideration is given that cork material and corks stored in premises with an atmosphere polluted by chloroanisoles may contaminate bottled wine aged in healthy cellars.
Methods for effective deodorization of cork have been studied, and the following methods have been attempted.